Office for National Statistics figures show there were 3,129 conceptions to women aged between 15 and 44 in the city in 2020 – down from 3,263 in 2019.
They were among 817,515 conceptions nationally, marginally down from 821,089 the year prior and marking the fifth consecutive annual fall.
Women aged between 30 and 34 had the most conceptions – in the south east the conception rate among women in this age bracket was 139.4 per 1,000 people in 2020.
The British Pregnancy Advisory Service (BPAS) said the pandemic and measures introduced in response ‘have clearly had very different impacts’ on the reproductive choices of women of different ages and backgrounds.
This includes a steep 17 per cent drop in young pregnancies among girls aged under 18, with the conception rate plummeting from 15.8 per 1,000 girls in 2019 to 13.1 per 1,000 people in 2020.
The teenage conception rate is now at its lowest point since records began, having fallen every year since 2007.
Of them, 72 were in Portsmouth – up from 65 in 2019.
Katherine O’Brien, spokeswoman for BPAS, said: ‘Lockdown restrictions which prevented socialising with anyone other than members of your own household will have had a greater impact on women in younger age groups, who will be less likely to have been co-habiting with partners.
‘This may be reflected in the sharp decrease in conception rates among those aged under 20, with conceptions rates among under-18s now standing at a record low.’
She said women on low incomes will be feeling anxious about their employment prospects and finances amid the cost-of-living crisis, adding that ‘these challenges are playing a very significant role in pregnancy decision making.’
But a fall in conceptions nationally has not led to a drop in births, Dr James Tucker, head of health and life events analysis at the ONS, explained.
‘Provisional births data indicate that 2021 births actually increased, but that this varied over the year,’ said Dr Tucker.
‘The first half of 2021 saw a decrease in births, all of which would have been conceived in 2020 when conceptions decreased; while the second half of 2021 saw an increase in births, which related to conceptions at the end of 2020 and beginning of 2021.’